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<div class="moz-cite-prefix">Must have something to do with windows
and or memory ..<br>
I use ST_Intersects daily on a Linux Server (PostGIS 2.0, PG
9.1.6) with a quad core Xeon and 16gb memory<br>
it takes milliseconds on much larger layers ..<br>
<br>
<div class="moz-signature"><b>Jeff Lake</b><br>
<a href="http://www.michiganwxsystem.com">MichiganWxSystem</a><br>
<a href="http://www.allisonhouse.com">AllisonHouse</a><br>
<a href="http://www.grlevelxstuff.com">GRLevelXStuff</a></div>
On 11/28/2012 16:22, Étienne Desgagné wrote:<br>
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<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Verdana","sans-serif";color:black;background:white"
lang="EN-US">Hello,<span class="apple-converted-space"> </span></span><span
style="font-size:7.5pt;font-family:"Verdana","sans-serif";color:black"
lang="EN-US"><br>
<br>
<span style="background:white"> I don't want to denigrate
PostGIS in any way and I know that my comparison may be
wrong but I'm trying to understand why a basic
ST_Intersection of two relatively small layers (< 1000
polygons) take about 1m40 sec in PostGIS(2.0 on PG 9.2 on
Windows) while applying the ArcGIS Intersect on same
layers and machine take about 2 sec?<span
class="apple-converted-space"> </span></span><br>
<br>
<span style="background:white">I'm aware of some PostgreSQL
tuning settings but even applying basic tuning
recommendation for PostGIS I'm facing the same problem...<span
class="apple-converted-space"> </span></span><br
style="orphans: 2;text-align:start;widows:
2;-webkit-text-size-adjust:
auto;-webkit-text-stroke-width: 0px;word-spacing:0px">
<br>
<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Verdana","sans-serif";color:black"
lang="EN-US">My two layers also have a spatial index.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:7.5pt;font-family:"Verdana","sans-serif";color:black"
lang="EN-US"><br>
<span style="background:white">Is it normal behavior? Any
suggestion for reaching better performance?<span
class="apple-converted-space"> </span></span><br>
<br>
<span style="background:white">Note that I'm also using
ST_Intersects on the join to filter only intersecting
features...<span class="apple-converted-space"> </span></span><br>
<br>
</span><span
style="font-size:7.5pt;font-family:"Verdana","sans-serif";color:black;background:white">Thanks
a lot<span class="apple-converted-space"> </span></span><span
style="font-size:7.5pt;font-family:"Verdana","sans-serif";color:black"><br>
<br>
<span style="background:white">Etienne</span></span><o:p></o:p></p>
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